Math Problem Statement

( √2+1)⁴=

Solution

To solve (2+1)4(\sqrt{2} + 1)^4, we can use the binomial theorem, which states that:

(a+b)n=k=0n(nk)ankbk(a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k

Here, a=2a = \sqrt{2}, b=1b = 1, and n=4n = 4. Applying the binomial theorem, we have:

(2+1)4=k=04(4k)(2)4k(1)k(\sqrt{2} + 1)^4 = \sum_{k=0}^{4} \binom{4}{k} (\sqrt{2})^{4-k} (1)^k

This simplifies to:

(2+1)4=(40)(2)4(1)0+(41)(2)3(1)1+(42)(2)2(1)2+(43)(2)1(1)3+(44)(2)0(1)4(\sqrt{2} + 1)^4 = \binom{4}{0} (\sqrt{2})^4 (1)^0 + \binom{4}{1} (\sqrt{2})^3 (1)^1 + \binom{4}{2} (\sqrt{2})^2 (1)^2 + \binom{4}{3} (\sqrt{2})^1 (1)^3 + \binom{4}{4} (\sqrt{2})^0 (1)^4

Calculating each term separately:

  1. (40)(2)4(1)0=141=4\binom{4}{0} (\sqrt{2})^4 (1)^0 = 1 \cdot 4 \cdot 1 = 4
  2. (41)(2)3(1)1=4221=82\binom{4}{1} (\sqrt{2})^3 (1)^1 = 4 \cdot 2\sqrt{2} \cdot 1 = 8\sqrt{2}
  3. (42)(2)2(1)2=621=12\binom{4}{2} (\sqrt{2})^2 (1)^2 = 6 \cdot 2 \cdot 1 = 12
  4. (43)(2)1(1)3=421=42\binom{4}{3} (\sqrt{2})^1 (1)^3 = 4 \cdot \sqrt{2} \cdot 1 = 4\sqrt{2}
  5. (44)(2)0(1)4=111=1\binom{4}{4} (\sqrt{2})^0 (1)^4 = 1 \cdot 1 \cdot 1 = 1

Summing these results:

4+82+12+42+1=17+1224 + 8\sqrt{2} + 12 + 4\sqrt{2} + 1 = 17 + 12\sqrt{2}

So,

(2+1)4=17+122(\sqrt{2} + 1)^4 = 17 + 12\sqrt{2}

Would you like further details or have any questions?

Here are some related questions for further practice:

  1. What is the expansion of (21)4(\sqrt{2} - 1)^4?
  2. How do you simplify (3+1)3(\sqrt{3} + 1)^3?
  3. What is the value of (2+3)2(2 + \sqrt{3})^2?
  4. How do you use the binomial theorem to expand (x+y)5(x + y)^5?
  5. What are the coefficients in the expansion of (x1)4(x - 1)^4?
  6. How do you find the middle term in the expansion of (a+b)6(a + b)^6?
  7. What is the expansion of (5+2)3(\sqrt{5} + 2)^3?
  8. How do you simplify (31)3(\sqrt{3} - 1)^3?

Tip: When working with the binomial theorem, it's often helpful to write out a few terms to identify patterns before calculating the entire expansion.

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Math Problem Analysis

Mathematical Concepts

Binomial Theorem
Simplification of Radical Expressions

Formulas

Binomial theorem: (a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k

Theorems

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Suitable Grade Level

Advanced High School